Minoxidil is called 6-(1-piperidinyl)-2,4-pyrimidinediamine-3-oxide by the chemical name, and described to be adaptable as a hair growth agent in U.S. Pat. No. 4,139,619.
In the past, minoxidil-containing hair growth preparations needed to be applied several times per day, therefore such application is very troublesome and tends to be forgotten, as a result, there are instances where an insufficient hair growth effect is seen.